Air Ride 911 - here comes hoopty clause

[doozer]

Ok I am bringing this up again...

Why not an air ride system for the 911? I have been kicking this idea around and the real problem seemed to be the front struts...

Well.. RideTech have come out with air sleeve over adjustable QA1 struts for a number of foreign cars so this takes me one step closer.

I think I can take their 4" Air Ride Strut and CNC a adaptor to plug into a shortened 911 strut body.

This would give me an on the fly adjustable spring so I could stay low and hit the " high water " setting to get over those nasty curbs and car trailer lips.

Any input???



http://www.ridetech.com/productinfo/airstrut.asp




I would use something like this on the rear with a custom mount:

[masraum]

Well, there were some early cars with pneumatic struts...

[doozer]

If designed correctly is there any drawbacks to the air ride suspension over the torsionbar or coil over??

I know the QA1 shock core is a really good unit.

[Lukesportsman]

I was just reading about a air ride conversion for another car tonight where they were very flattering of the ride and handling.

Here is my ignorant question that I've asked ever since the street rodders started using these: Doesn't the spring rate decrease the lower the car sits? If this is so, as air bags on trucks, wouldn't the best spring rate come from an excessive ride and CG?

I have an air bag suspension in the back of a 69 Buick that was designed for a multipurpose vehicle. It rides much harder as the car raises. Good for soft drag springs to make a reasonable street car, but can't figure out how this works specifically for handling.

[stlrj]

I'd like to see how you'd fit the rear air shock in a 911...not much room where it's supposed to go.

Take a peek behind the rear wheel...hummm.

You might have better luck with a set of pnuematic struts from GM.


-Joe

[Quicksilver]

The idea of what you want to do is something that I have thought through for a number of years and I’ve got a solution in mind but I had to work through a number of problems to get there.

Here is the problem as I see it. A car that gives so much ride detail and is intended to be used so close to the tires limits, like the 911, requires a very accurate suspension setup. A small difference in one corner’s preload can make a very noticeable difference in the suspension’s wedge.

How are you going to inflate the system? Lets only consider the front end for simplicity. On the most simplistic level you want equivalent air to be put in each airbag. Is that equivalent air pressure? Only if the car is on a flat and true surface and the weight distribution from left to right is perfect. Are the two airbags fed from a common manifold? If so the air will transfer from side to side, reducing the roll resistance. That won’t work for a 911. If the right and left have a separate system then how do you insure that you have the correct quantity of air for each side, independent of the variations in the surface under the car at the time of adjustment? Two pumps giving equivalent pressure won't do it. The only way I see that it could work is by feeding it with a ram (hydraulic or air) that you can move a known, calibrated distance.

The solution for this problem that I like is to use conventional coilovers and mount them to some sort of a screw-jack arrangement. If you motorize it and use basic servo controls you can move the coilover’s mounting point by a known, calibrated, repeatable distance. It should be pretty easy to arrange it to move fairly quickly. I am thinking of a mounting point that is on a bellcrank so the electrical screwjack can be aimed up at it from inside of the inner fenderwell.

My 4 cents. . . (inflation!)

Wayne

[stlrj]

So far the best solution I have found for myself is the stock system where all I need is an 11mm socket for the front and a 36mm bike wrench for the rear that's good for about 2 to 3" in about 10 min.

-Joe

[doozer]

Quicksilver - I had looked at hydraulic adjustment, and the electrical screw system works well if the suspension is unloaded ( on jacks ).

What I was considering was a single compressor - four corner system ( all corners independent ). They make a little computer that controls four corner systems both by pressure and by a ride height sensor on each corner. From what I understand so far is that they are very accurate.

My question was more of function at the correct height. Will the ride quality suffer compared to a four corner coil over setup? Can you autocross on air ride??

thanks
Todd

[doozer]

stlrj - I have a lot of extra room to attach rear coil-overs or air ride, as the factory sheet metal arch member that accepts the rear shocks has been removed and replaced with two 1.75 x .134 tubing with shock eyes welded to it.

[asphaltgambler]

""Here is my ignorant question that I've asked ever since the street rodders started using these: Doesn't the spring rate decrease the lower the car sits? If this is so, as air bags on trucks, wouldn't the best spring rate come from an excessive ride and CG?""

Yes!!!!!!!!! There is only one sweet spot (PSI) for air ride where the ride, travel and handling all come together. You can bet it's not where the cars' stance looks the best.

[doozer]

Here is a shot of the four corner level sensor:

[doozer]

I got some feedback yesterday from some friends in the sport compact field who successfully race and autocross on four corner independent air suspension. They actually prefer it

There may just be a lot of tricks to getting it correct.

[doozer]

Well a bunch of experimenting and calculating and I am about to start building the front air spring over shock setup:

More Details:
http://hypertec.ws/todd_porsche/photos/air_ride/air_ride.html

[Lukesportsman]

I'm trying to think, last week (Sunday) I was watching a Speedvision program on just this. It might have been Sports Car Revolution, yet I don't remember. They showed a get together put on in my own backyard at Putnam Park Raceway last fall by a manufactor (AirRide???). They had a couple known race car drivers and did both subjective and objective testing of several cars including Camaros and Mustangs along with many "Hot Rods".

They tested them on quarter mile, slalom, braking, and road course. Visually, the cars improved substantially over an OEM. They even did a live conversion with back to back testing of a late model Camaro. It improved both visually and by timing equipment. The pro drivers seemed to be impressed.

This obviously doesn't guarantee that it will transfer to a 911, but our earlier thread came to mind. I was VERY impressed with this technology in a performance setting.

I will have to change my previous prejudice ideas of this suspension. Won over, not yet. More curious than ever, YES!

[doozer]

Well I will be the GinnyPig on this one!

Yes it was the company I am working with " Air Ride Technologies " http://www.ridetech.com

[autoxracer31]

Look at the whirlwind I started... So amazing that this many people like the thought of air ride and no company besides our industrious at home pelicans will work on a system for our beloved 911s

[PorscheGuy79]

Looking good doozer

[doozer]

Dare you = Mother of invention

Thanks Mathew!

[TXScott]

Just think about service benifits.....no more floor jack needed
Hmmmmm
Endless posibilities
SG

[randywebb]

How long until the Bose active suspension makes this obsolete?